501-600

('$' means the problem is locked on Leetcode, '*' means the problem is related to Database, '#' means the problem is related to Shell.)

#	Title	Solution	Difficulty
600	Non-negative Integers without Consecutive Ones	27.40%	Hard
599	Minimum Index Sum of Two Lists	48.00%	Easy
598	Range Addition II	48.30%	Easy
597	Friend Requests I: Overall Acceptance Rate $	38.40%	Easy
596	Classes More Than 5 Students	33.40%	Easy
595	Big Countries	72.00%	Easy
594	Longest Harmonious Subsequence	40.00%	Easy
593	Valid Square	39.20%	Medium
592	Fraction Addition and Subtraction	47.00%	Medium
591	Tag Validator	26.40%	Hard
590	N-ary Tree Postorder Traversal	63.00%	Easy
589	N-ary Tree Preorder Traversal	63.10%	Easy
588	Design In-Memory File System $	32.40%	Hard
587	Erect the Fence	29.90%	Hard
586	Customer Placing the Largest Number of Orders $	62.50%	Easy
585	Investments in 2016 $	44.60%	Medium
584	Find Customer Referee $	63.60%	Easy
583	Delete Operation for Two Strings	44.00%	Medium
582	Kill Process $	47.70%	Medium
581	Shortest Unsorted Continuous Subarray	30.10%	Easy
580	Count Student Number in Departments $	40.00%	Medium
579	Find Cumulative Salary of an Employee $	30.90%	Hard
578	Get Highest Answer Rate Question $	33.10%	Medium
577	Employee Bonus $	53.80%	Easy
576	Out of Boundary Paths	33.10%	Medium
575	Distribute Candies	59.50%	Easy
574	Winning Candidate $	34.50%	Medium
573	Squirrel Simulation $	51.00%	Medium
572	Subtree of Another Tree	41.00%	Easy
571	Find Median Given Frequency of Numbers $	44.90%	Hard
570	Managers with at Least 5 Direct Reports $	59.00%	Medium
569	Median Employee Salary $	41.60%	Hard
568	Maximum Vacation Days $	39.90%	Hard
567	Permutation in String	36.30%	Medium
566	Reshape the Matrix	59.80%	Easy
565	Array Nesting	50.00%	Medium
564	Find the Closest Palindrome	16.60%	Hard
563	Binary Tree Tilt	47.00%	Easy
562	Longest Line of Consecutive One in Matrix $	38.80%	Medium
561	Array Partition I	69.80%	Easy
560	Subarray Sum Equals K	41.80%	Medium
559	Maximum Depth of N-ary Tree	62.10%	Easy
558	Quad Tree Intersection	36.40%	Easy
557	Reverse Words in a String III	61.20%	Easy
556	Next Greater Element III	27.70%	Medium
555	Split Concatenated Strings $	30.00%	Medium
554	Brick Wall	42.70%	Medium
553	Optimal Division	55.20%	Medium
552	Student Attendance Record II	28.50%	Hard
551	Student Attendance Record I	43.90%	Easy
549	Binary Tree Longest Consecutive Sequence II $	38.10%	Medium
548	Split Array with Equal Sum $	30.80%	Medium
547	Friend Circles	49.00%	Medium
546	Remove Boxes	29.60%	Hard
545	Boundary of Binary Tree $	29.10%	Medium
544	Output Contest Matches $	73.20%	Medium
543	Diameter of Binary Tree	42.70%	Easy
542	01 Matrix	32.50%	Medium
541	Reverse String II	44.40%	Easy
540	Single Element in a Sorted Array	55.90%	Medium
539	Minimum Time Difference	44.70%	Medium
538	Convert BST to Greater Tree	52.70%	Medium
537	Complex Number Multiplication	65.90%	Medium
536	Construct Binary Tree from String $	36.30%	Medium
535	Encode and Decode TinyURL	76.10%	Medium
534	Design TinyURL	N/A	Medium
533	Lonely Pixel II $	38.90%	Medium
532	K-diff Pairs in an Array	27.20%	Easy
531	Lonely Pixel I $	50.20%	Medium
530	Minimum Absolute Difference in BST	48.00%	Easy
529	Minesweeper	52.00%	Medium
528	Random Pick with Weight	41.80%	Medium
527	Word Abbreviation $	33.90%	Hard
526	Beautiful Arrangement	53.50%	Medium
525	Contiguous Array	34.40%	Medium
524	Longest Word in Dictionary through Deleting	40.20%	Medium
523	Continuous Subarray Sum	21.3	Medium
522	Longest Uncommon Subsequence II	28.10%	Medium
521	Longest Uncommon Subsequence I	50.70%	Easy
520	Detect Capital	54.20%	Easy
519	Random Flip Matrix	32.20%	Medium
518	Coin Change 2	33.20%	Medium
517	Super Washing Machines	34.60%	Hard
516	Longest Palindromic Subsequence	42.00%	Medium
515	Find Largest Value in Each Tree Row	52.70%	Medium
514	Freedom Trail	27.20%	Hard
513	Find Bottom Left Tree Value	55.60%	Medium
510	Inorder Successor in BST II $	56.20%	Medium
509	Fibonacci Number	66.40%	Easy
508	Most Frequent Subtree Sum	52.00%	Medium
507	Perfect Number	32.70%	Easy
506	Relative Ranks	48.50%	Easy
505	The Maze II	34.80%	Medium
504	Base 7	46.40%	Easy
503	Next Greater Element II	46.20%	Medium
502	IPO	32.40%	Hard
501	Find Mode in Binary Search Tree	39.40%	Easy